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Move all intrinsic whitelists into the constness check file

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This commit is contained in:
Oliver Scherer 2019-11-26 12:55:11 +01:00
parent 52be0b07ae
commit 46c00a21e1
4 changed files with 42 additions and 56 deletions
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35
src/librustc/ty/constness.rs
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@ -36,12 +36,47 @@ impl<'tcx> TyCtxt<'tcx> {
}
}
/// Returns `true` if the `def_id` refers to an intrisic which we've whitelisted
/// for being called from stable `const fn`s (`min_const_fn`).
///
/// Adding more intrinsics requires sign-off from @rust-lang/lang.
fn is_intrinsic_min_const_fn(self, def_id: DefId) -> bool {
match self.item_name(def_id) {
| sym::size_of
| sym::min_align_of
| sym::needs_drop
// Arithmetic:
| sym::add_with_overflow // ~> .overflowing_add
| sym::sub_with_overflow // ~> .overflowing_sub
| sym::mul_with_overflow // ~> .overflowing_mul
| sym::wrapping_add // ~> .wrapping_add
| sym::wrapping_sub // ~> .wrapping_sub
| sym::wrapping_mul // ~> .wrapping_mul
| sym::saturating_add // ~> .saturating_add
| sym::saturating_sub // ~> .saturating_sub
| sym::unchecked_shl // ~> .wrapping_shl
| sym::unchecked_shr // ~> .wrapping_shr
| sym::rotate_left // ~> .rotate_left
| sym::rotate_right // ~> .rotate_right
| sym::ctpop // ~> .count_ones
| sym::ctlz // ~> .leading_zeros
| sym::cttz // ~> .trailing_zeros
| sym::bswap // ~> .swap_bytes
| sym::bitreverse // ~> .reverse_bits
=> true,
_ => false,
}
}
/// Returns `true` if this function must conform to `min_const_fn`
pub fn is_min_const_fn(self, def_id: DefId) -> bool {
// Bail out if the signature doesn't contain `const`
if !self.is_const_fn_raw(def_id) {
return false;
}
if let Abi::RustIntrinsic = self.fn_sig(def_id).abi() {
return self.is_intrinsic_min_const_fn(def_id);
}
if self.features().staged_api {
// in order for a libstd function to be considered min_const_fn